【发布时间】：2017-07-25 19:06:15
【问题描述】：
我正在开发一个测验应用程序，在要求您回答问题的初始视图控制器之后出现了第二个视图控制器。在第二个视图控制器上，用户必须按下一个按钮才能返回到初始视图控制器以被问到另一个问题。但是，当我从第二个视图控制器返回时，我相信正在创建初始视图控制器的新实例，并且会向用户询问他们已经回答的问题。我的初始视图控制器的 swift 文件中的代码是这样构造的，当用户被问到一个问题时，一旦该问题通过它的索引从数组中删除。我怎样才能使它的初始视图控制器的新实例不是通过从第二个视图控制器进行 segue 而创建的？或者有没有办法第二个视图控制器可以访问与初始视图控制器相同的方法？
这是我的初始视图控制器代码：
import UIKit
class ViewController: UIViewController {
var questionList = [String]()
func updateCounter() {
counter -= 1
questionTimer.text = String(counter)
if counter == 0 {
timer.invalidate()
wrongSeg()
counter = 15
}
}
func randomQuestion() {
//random question
if questionList.isEmpty {
questionList = Array(QADictionary.keys)
questionTimer.text = String(counter)
}
let rand = Int(arc4random_uniform(UInt32(questionList.count)))
questionLabel.text = questionList[rand]
//matching answer values to go with question keys
var choices = QADictionary[questionList[rand]]!
questionList.remove(at: rand)
//create button
var button:UIButton = UIButton()
//variables
var x = 1
rightAnswerBox = arc4random_uniform(4)+1
for index in 1...4
{
button = view.viewWithTag(index) as! UIButton
if (index == Int(rightAnswerBox))
{
button.setTitle(choices[0], for: .normal)
}
else {
button.setTitle(choices[x], for: .normal)
x += 1
}
randomImage()
}
}
let QADictionary = ["Who is Thor's brother?" : ["Atum", "Loki", "Red Norvell", "Kevin Masterson"], "What is the name of Thor's hammer?" : ["Mjolinr", "Uru", "Stormbreaker", "Thundara"], "Who is the father of Thor?" : ["Odin", "Sif", "Heimdall", "Balder"]]
//wrong view segue
func wrongSeg() {
performSegue(withIdentifier: "incorrectSeg", sender: self)
}
//proceed screen
func rightSeg() {
performSegue(withIdentifier: "correctSeg", sender: self)
}
//variables
var rightAnswerBox:UInt32 = 0
var index = 0
//Question Label
@IBOutlet weak var questionLabel: UILabel!
//Answer Button
@IBAction func buttonAction(_ sender: AnyObject) {
if (sender.tag == Int(rightAnswerBox))
{
rightSeg()
print ("Correct!")
}
if counter != 0 {
counter = 15
questionTimer.text = String(counter)
}
else if (sender.tag != Int(rightAnswerBox)) {
wrongSeg()
print ("Wrong!")
timer.invalidate()
questionList = []
}
randomQuestion()
}
override func viewDidAppear(_ animated: Bool)
{
randomQuestion()
}
//variables
var counter = 15
var timer = Timer()
@IBOutlet weak var questionTimer: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
timer = Timer.scheduledTimer(timeInterval: 1, target:self, selector: #selector(ViewController.updateCounter), userInfo: nil, repeats: true)
}
这是第二个视图控制器的代码：
import UIKit
class ContinueScreen: UIViewController {
//correct answer label
@IBOutlet weak var correctLbl: UILabel!
//background photo
@IBOutlet weak var backgroundImage: UIImageView!
func backToQuiz() {
if let nav = self.navigationController {
nav.popViewController(animated: true)
}
else {
self.dismiss(animated: true, completion: nil)
}
}
@IBAction func `continue`(_ sender: Any) {
backToQuiz()
}
【问题讨论】：
标签： swift delegates segue viewcontroller navigationcontroller